Predicting thyroxine requirements following total thyroidectomy.

OBJECTIVE: Optimal thyroxine replacement following total thyroidectomy is critical to avoid symptoms of hypothyroidism. The aim of this study was to determine the best formula to determine the initiated replacement dose of levothyroxine immediately following total thyroidectomy. DESIGN: Prospective study. All patients were initiated on 100 µg levothyroxine and titrated to within the reference range for TSH and free T4. Correlations to height, weight, age, lean body mass (LBM), body surface area (BSA) and body mass index (BMI) were calculated. PATIENTS: One hundred consecutive adult patients underwent total thyroidectomy for non-malignant disease. MEASUREMENTS: Comparison between three methods of levothyroxine dose prediction, aiming for a levothyroxine dose correct to within 25 µg of actual dose required. RESULTS: Correlations were seen between levothyroxine dose and patient age (r=-0.346, P<0.01), bodyweight (r=0.296, P<0.01), LBM (r=0.312, P<0.01), BSA (r=0.319, P<0.01) and BMI (r=0.172, P<0.05). A regression equation was calculated (predicted levothyroxine dose=[0·943 × bodyweight] + [-1.165 × age] + 125.8), simplified to (levothyroxine dose= bodyweight - age + 125) pragmatically. Initiating patients empirically on 100 µg post-operatively showed that 40% of patients achieved target within 25 µg of their required dose; this increased to 59% when using a weight-only dose calculation (1.6 µg/kg) and to 72% using the simplified regression equation. CONCLUSIONS: A simple calculated regression equation gives a more accurate prediction of initiated levothyroxine dose following total thyroidectomy, reducing the need for outpatient attendance for dose titration.

Dysphagia with a thyroid nodule: is there a primary aerodigestive malignancy?

Three cases of laryngopharyngeal primary squamous cell carcinoma presenting with thyroid nodules are described. The key message to take away from these cases is that patients with advanced malignancy of the upper aerodigestive tract can present with a thyroid nodule.

The isolation and characterisation of primary human laryngeal epithelial cells.

We have shown that the larynx has a prominent immunological component that varies between individuals, and which is influenced by lifestyle factors implicated in the pathogenesis of the inflammatory and neoplastic diseases of the larynx. In order to explore the mechanisms of such links between laryngeal mucosal immunity and the development of lifestyle-related disease, reliable in vitro models are essential. In this study, we isolated and characterised primary laryngeal epithelial cells from normal individuals and show they can be cultured and manipulated to express MHC class II molecules in vitro.

Smoking influences the immunological architecture of the human larynx.

Little is known about the effects of demographic and lifestyle factors on laryngeal mucosal immunology. Pinch biopsies of laryngeal mucosa were studied from 63 patients without laryngeal disease. Areas of positive staining for HLA-DR, HLA-DQ, HLA-DP, CD45, CD45RA, CD45RO, CD4, CD8, and CD79 were calculated. Patients were stratified according to gender and smoking status. Analysis of covariance showed current cigarette smokers had increased numbers of CD4+ T cells and there was an association between older age and greater CD4+ T cell numbers in both epithelium and lamina propria. Older age and female gender were associated with decreased lamina propria CD4+ CD45RO+ T cells and an increase in CD4+ CD45RO- T cells. T cell populations in the larynx may therefore be influenced by smoking, age and gender. We hypothesize that smoking induces changes in normal immunological function of the larynx, which may contribute to the etiology of inflammatory disease and cancer.